The overall objective of my work is to determine how the mammalian brain stem functions to integrate sensory inputs and intrinsic respiratory activity to produce an appropriate respiratory motor response. My efforts will concentrate upon the dorsal respiratory group (DRG) of neurons in the medulla of cat. I believe these cells are the initial intracranial processing station for many visceral reflexes affecting respiration. I intend to identify the sensory inputs to these cells and the role of these cells in reflex responses to these inputs. To do this we are employing the technique of spike triggered averaging. In addition, we will inject intracellularly the enzyme marker horseradish to determine anatomical-functional correlates of single identified DRG neurons. These results will help to establish the role and function in respiration of this key collection of brain stem neurons.